In mobile communication systems including a plurality of base stations, predetermined signals such as a health check signal and a paging signal have been periodically transmitted to the base stations. Conventional technologies are disclosed in, for example, Japanese Laid-open Patent Publication No. H5-108509 and Japanese Laid-open Patent Publication No. H8-223191. The health check signal is a signal to check an operation state of the base stations, and the paging signal is a signal to detect a mobile terminal to be connected.
As a base station that forms such a mobile communication system, a small base station that covers a smaller range (a few meters to a few tens of meters) than that of an existing base station has been developed. The small base station, for example, has been developed to provide a good quality service even in places where radio waves are hard to reach, such as indoors and underground.
The small base station covers a range much smaller than that of the existing base station (hereinafter, referred to as “large base station”), and because an individual cell is small, a large number of small base stations can be installed in a network.
Accordingly, when the small base stations are installed, a significantly large number of base stations may be present in the mobile communication system, compared with that of the existing system. If the significantly large number of base stations is present in the mobile communication system in this manner, a large load is applied to a transmitting node that transmits a predetermined signal to each base station. Accordingly, provision of various services may be adversely affected.